Filled/Skeletal. Composed of a continuous skeletal matrix filled by a second material. Laminar. Composed of layers (lamina) bonded together by a matrix material. The fiber composite classification in Table 1.1 can be further structured for identification by noting the direction and placement of fibers. This results in Figure 1.1 for classification of fiber-reinforced composite types (a) Continuous fiber composite (b) Woven fiber composito (c)Chopped fiber composite FIGURE L.l. Types of Fiber-Reinforced Composites A further classification of the woven composite configurations, shown in(b) above, is illustrated in the geometric architectures shown below in Figure 1.2
3 Filled/Skeletal. Composed of a continuous skeletal matrix filled by a second material. Laminar. Composed of layers (lamina) bonded together by a matrix material. The fiber composite classification in Table 1.1 can be further structured for identification by noting the direction and placement of fibers. This results in Figure 1.1 for classification of fiber-reinforced composite types. A further classification of the woven composite configurations, shown in (b) above, is illustrated in the geometric architectures shown below in Figure 1.2
(a)Orthogonal (b)Cylindrical structure (c) (d) Braided structure (e) Orthogonal interlock structure (f) Angle interlock structure FIGURE 1. 2. Types of Woven Fiber-Reinforced Composites Of the composite material types described in Table 1.1, fiber composites have received considerable attention in recent years due to the development of advanced fiber types such as glass, Kevlar and graphite, which have moduli in excess of 3x106 psi/20 GPa. The incorporation of these fiber types into suitable binders/ matrices, which may be metals, non-metals or ceramics, leads to a synergism in which the new material possesses unique properties compared to the properties of either of the constituent elements. The acceleration of this material's revolution is depicted in Figure 1.3, which shows the state a maturity of various materials and, in particular, the status of composite materials
4 Of the composite material types described in Table 1.1, fiber composites have received considerable attention in recent years due to the development of advanced fiber types such as glass, Kevlar and graphite, which have moduli in excess of psi/20 GPa. The incorporation of these fiber types into suitable binders/matrices, which may be metals, non-metals or ceramics, leads to a synergism in which the new material possesses unique properties compared to the properties of either of the constituent elements. The acceleration of this material’s revolution is depicted in Figure 1.3, which shows the state a maturity of various materials and, in particular, the status of composite materials
tles Specialty metals Carbon High-performance engineering plastlcs Englneering plastles; alloys and ble Advanced parmer matrx composites Advanced metamatrix composites Heavy R&D Rapld growth GrowthGrowth Growth <GDP GURE 13. State of materia This leads to a definition of a composite material, which has been defined in ASTMD 3878-95c as: Composite Material. A substance consisting of two or more materials, insoluble in one another, which are combined to form a useful engineering material possessing certain properties not possessed by the constituents which the constituents of a composi material are engineered is critical to the performance of the material system. Composites consisting of fibers embedded in a suitable matrix(binder) material can consist of several configurations dependent upon whether the embedded fibers are continuous or discontinuous. The configurations are: Discontinuous, fiber-reinforced composite- A composite material which consists of chopped fibers or whiskers embedded within a matrix material Fabric reinforced composite- A composite material in which the embedded fiber assembly consists of a fabric, which may be woven, knitted or braided. Fiber-reinforced composite-A composite material which consists of embedded ous/discontinuous fibers in a matrix material
5 This leads to a definition of a composite material, which has been defined in ASTM D 3878-95c as: “Composite Material. A substance consisting of two or more materials, insoluble in one another, which are combined to form a useful engineering material possessing certain properties not possessed by the constituents.” As previously discussed, the way in which the constituents of a composite material are engineered is critical to the performance of the material system. Composites consisting of fibers embedded in a suitable matrix (binder) material can consist of several configurations dependent upon whether the embedded fibers are continuous or discontinuous. The configurations are: Discontinuous, fiber-reinforced composite – A composite material which consists of chopped fibers or whiskers embedded within a matrix material. Fabric reinforced composite – A composite material in which the embedded fiber assembly consists of a fabric, which may be woven, knitted or braided. Fiber-reinforced composite – A composite material which consists of embedded continuous/discontinuous fibers in a matrix material
Filamentary composite- A composite material reinforced by continuous fibers embedded in a matrix material Unidirectional fiber-reinforced erial in which all th embedded fibers are all aligned in a single direction 1.3 Types of Composite Materials The important types of advanced composites can be depicted in the pie chart shown in Figure 14 be which describes the five principal types of advanced composite material in wide use. CRSS MM C C Carbon/Carbon FIGURE 1. 4. Principal Composite Materials The composite types cited in Figure 1.4 include Polymer Matrix Composites (PMC), Metal Matrix Composites(MMC), Ceramic Matrix Composites(CMC), Carbon Carbon(CC) and Hybrids consisting of a combination of the previously mentioned matrices and/or fiber In composite materials in 2001, glass fibers are the most used, and electrical or E- glass fibers account for more than 90% of all glass fibers used. S-glass fibers comprise the other 10% and are typically forty to seventy percent stronger than E-glass. Also, S-2 glass fibers were developed in the 1960,'s for military application
6 Filamentary composite – A composite material reinforced by continuous fibers embedded in a matrix material. Unidirectional fiber-reinforced composite – A composite material in which all the embedded fibers are all aligned in a single direction. 1.3 Types of Composite Materials The important types of advanced composites can be depicted in the pie chart shown in Figure 1.4 below, which describes the five principal types of advanced composite material in wide use. The composite types cited in Figure 1.4 include Polymer Matrix Composites (PMC), Metal Matrix Composites (MMC), Ceramic Matrix Composites (CMC), CarbonCarbon (CC) and Hybrids consisting of a combination of the previously mentioned matrices and/or fibers. In composite materials in 2001, glass fibers are the most used, and electrical or Eglass fibers account for more than 90% of all glass fibers used. S-glass fibers comprise the other 10% and are typically forty to seventy percent stronger than E-glass. Also, S-2 glass fibers were developed in the 1960’s for military applications
The other two fiber types most often used in composite materials today are carbon and aramid ( Kevlar)fibers As to matrix materials by far the most often used are polymeric resins. Metal and ceramic matrix materials are used only for special applications. The polymeric resins fall into two categories: thermosets and thermoplastics. Thermoset resins become cross linked during cure and the result is a final rigid configuration. Thermoplastic resins are processed at higher temperatures and remain plastic, can be reheated and can be shaped. However, the majority of polymeric resins used in composites in 2001are thermosets Thermosets- This matrix can be characterized by having polymer chains that become highly cross-linked during cure. Once it is cured, it is in a final rigid configuration and there is nothing that will change it(short of a failure of the atrix). These matrices are advantageous for high temperature applications of Among most often used thermoset resins are unsaturated polyester, halogenated polyester, vinylester, epoxy, phenolic, polyurethane and polybutadiene Thermoplastics-This matrix can be characterized by having polymer chains that re not cross-linked. It can be remolded to a new when heated to ame temperature at which it wa atrices, the operating temperature should be kept below the cure temperature. Among the thermoplastic resins the most often used include polyethylene, olystyrene, polypropylene, acryonitride-butadiene styrene(ABS), acetal, polycarbonate PC), polyvinyl chloride(PVC), polysulfone(PSF), polyphenylene sulfide(PPS)and nylon(semi-crystalline polymide)
7 The other two fiber types most often used in composite materials today are carbon and aramid (Kevlar) fibers. As to matrix materials by far the most often used are polymeric resins. Metal and ceramic matrix materials are used only for special applications. The polymeric resins fall into two categories: thermosets and thermoplastics. Thermoset resins become crosslinked during cure and the result is a final rigid configuration. Thermoplastic resins are processed at higher temperatures and remain plastic, can be reheated and can be reshaped. However, the majority of polymeric resins used in composites in 2001 are thermosets. Thermosets – This matrix can be characterized by having polymer chains that become highly cross-linked during cure. Once it is cured, it is in a final rigid configuration and there is nothing that will change it (short of a failure of the matrix). These matrices are advantageous for high temperature applications of composites. Among the most often used thermoset resins are unsaturated polyester, halogenated polyester, vinylester, epoxy, phenolic, polyurethane and polybutadiene. Thermoplastics – This matrix can be characterized by having polymer chains that are not cross-linked. It can be remolded to a new shape when heated to approximately the same temperature at which it was cured. When using these matrices, the operating temperature should be kept below the cure temperature. Among the thermoplastic resins the most often used include polyethylene, polystyrene, polypropylene, acryonitride-butadiene styrene (ABS), acetal, polycarbonate (PC), polyvinyl chloride (PVC), polysulfone (PSF), polyphenylene sulfide (PPS) and nylon (semi-crystalline polymide)